Wow, I can't see doing all that work and not replacing everything. 
I can......

First homer most likely did all the work and the owner watched and "advised"... Did I get that right homer?
If it was me and in about 2 or 3 weeks when the clutch goes I'd tell him "been there done that sorry about your luck". Since you have a good idea about the time involved then quote him the cost of the job at a reasonable labour rate,say 20 bucks per hour!
When I contracted I used to do a few renos and I would always tell the home owner I'd have to charge double if they helped,after all they're learning a trade.....
